The present invention relates generally to an apparatus for demonstrating magnetic force and more particularly to such an apparatus wherein high permeance magnetic shielding is selectively displaced from an air gap between rotor-field magnet pairs.
In classroom instruction, particularly in teaching physics to young people, there is a trend toward providing laboratory demonstrations to illustrate physical phenomena. For example, in teaching magnetism, magnetic flux is often illustrated by disposing fine magnetic particles, such as iron filings, over a cardboard layer which is in turn placed over a magnet. The iron filings become oriented in a pattern corresponding to the lines of magnetic flux generated by the magnet.
In teaching the principles of magnetic force, it is particularly desirable to provide a demonstration to supplement the lecture. The demonstration should be dynamic and entertaining to attract and retain the attention of the students and to act as a memory aid. Furthermore, the demonstration should be simple to illustrate the phenomenon of magnetic force and permit the students themselves to operate the apparatus, yet be capable of illustrating all basic aspects of magnetic force, i.e., attraction, repulsion and the effect of magnetic shielding.